FIG. 1 shows an overview of a railroad 2 according to the prior art. In general, railroad 2 includes two parallel rails 4 (only one shown) that are periodically fastened to support rail support members (ties) 6. Ties 6 are generally embedded in a matrix of gravel, stone, and dirt called ballast 8. A rail vehicle 10 (e.g., locomotive, railroad car, wagon, coach, and/or the like) includes wheels 12 that travel along rails 4. Wheels 12 are attached to the rail vehicle 10 by a complex support and control mechanism, which is generally referred to as a truck 14. Truck 14 can include springs 16 and other components for reducing transmitted vibration and shock, a mechanism for braking the rail vehicle 10, mechanisms for coupling rail vehicle 10 to other rail vehicles, and/or the like. Rail vehicle 10, along with its truck 14, accompanying control systems (e.g., air, electrical, hydraulic, and/or the like), engine (e.g., for a locomotive), wheels 12, and/or the like, is referred to as the “rolling stock” of railroad 2. Multiple rail vehicles 10 that are coupled together are often referred to as a consist of rolling stock.
During operation, many aspects of the rolling stock are exposed to various forms of stress, which may cause wear and tear, and, without maintenance, eventual failure. To this extent, various aspects of the rolling stock can be examined for safety and maintenance purposes. For example, wheels 12, due to their constant rolling in contact with rails 4, can and do experience wear in various ways depending on the exact loading of the wheels 12 and rail 4. Over time, wheels 12 will eventually become overly worn, develop cracks or gouges, and/or the like, and can become unsafe for use as a result. Further, vibration and shock during use can cause truck 14 to crack. Still further, braking and other mechanisms will experience wear as a result of their operation.
In light of the above, it is necessary to inspect the various components of railroad 2 to ensure that worn components are refurbished or replaced before their wear becomes a danger. Given the vast scope of the railroad industry, this is a formidable undertaking and one in which a great deal of time and money has been invested. Inspections are often manually performed by an inspector, who may use one or more devices for obtaining accurate measurements of a particular railroad 2 component. For example, wheels 12 are regularly inspected using various devices, such as a mechanical caliper, a handheld electronic device (e.g., as described in U.S. Pat. No. 4,904,939), and/or the like. However, these manual inspections require that the rolling stock be stopped during the inspection and a manual measurement be performed, which costs a considerable amount of time.
Wayside systems have been proposed to automate the inspection of certain components of the rolling stock. Often, these systems have some or all of their components set into the ground to obtain placement close to tracks 4 and ties 6, while avoiding collision with a component of the rolling stock. Illustrative wayside systems include: a hot bearing detector (e.g., as described in U.S. Pat. No. 3,731,087); image-based wheel measurement systems (e.g., as described in U.S. Pat. Nos. 4,749,870, 5,636,026, 6,768,551); and an interior wheel 12 flaw detection system (e.g., as described in U.S. Pat. No. 6,523,411).
Current wayside systems can be difficult to align and calibrate multiple disparate components of the system so that accurate results are provided during operation. Further, in certain environments, the wayside systems often require weatherization, cleaning mechanisms, and the like, which add to the cost of implementing the systems and the complexity of designing and maintaining the systems. Still further, the wayside systems may interfere with standard railroad operation. For example, an automated system for maintaining tracks 4 and ties 6 is often used, which examines the spacing and set of ties 6 and will re-tamp a tie 6 into the ballast 8 when required. Such a system relies on precise limits for the size and spacing of ties 6, which may be altered to accommodate a wayside system. As a result, the automated track maintenance system may not be useable for the section of rail. Still further, a wayside system may interfere with track inspection and maintenance, which can result in damage or impedance to a maintenance machine or damage to the wayside system.
Additionally, railway switches, i.e., sections of moveable track that are used to selectively direct rolling stock along one of a plurality of possible tracks, may freeze or become jammed with snow. The failure of a switch to move or move its full distance can lead to a derailment or a collision. As a result, it is critical to ensure the proper movement of the switches. Several systems have been proposed including those described in U.S. Pat. Nos. 5,702,074, 4,674,718, and 4,695,017. Each of these systems vent heated air at particular locations along the track. One system pipes air through a conduit that comprises substantially the same size, shape, and support capability as that of a railroad tie 6.